﻿610 
  MR. 
  G. 
  W. 
  LAMPLTJGH 
  ON 
  THE 
  

  

  Belemnites 
  Owenii, 
  Pratt, 
  and 
  varieties. 
  

  

  The 
  specimens 
  of 
  Belemnites, 
  few 
  in 
  number, 
  found 
  in 
  the 
  shales 
  

   (F) 
  below 
  the 
  " 
  Coprolite-bed 
  " 
  have 
  all 
  been 
  referred 
  to 
  this 
  species, 
  

   but 
  they 
  represent 
  an 
  extreme 
  range 
  of 
  variation. 
  One 
  specimen 
  

   only 
  approaches 
  the 
  normal 
  form 
  of 
  the 
  species, 
  while 
  the 
  majority 
  

   belong 
  to 
  a 
  long 
  and 
  slender 
  variety, 
  often 
  deeply 
  channelled 
  

   throughout 
  a 
  great 
  part 
  of 
  its 
  length, 
  which, 
  were 
  it 
  thought 
  advis- 
  

   able 
  to 
  break 
  up 
  the 
  species, 
  might 
  be 
  considered 
  a 
  separate 
  form. 
  

   This 
  variety 
  comes 
  near 
  to 
  Bel. 
  spicularis, 
  Phillips, 
  from 
  the 
  Kime- 
  

   ridge 
  Clay 
  of 
  Cromarty, 
  as 
  figured 
  in 
  ' 
  Brit. 
  Bel.' 
  pi. 
  xxxviii. 
  f. 
  82 
  

   (1870, 
  p. 
  122). 
  Phillips, 
  in 
  his 
  'Geology 
  of 
  Yorkshire,' 
  3rd 
  ed. 
  

   (pi. 
  xxv. 
  f. 
  9) 
  has 
  also 
  figured 
  an 
  imperfect 
  specimen 
  of 
  this 
  variety 
  

   under 
  the 
  name 
  of 
  Bel. 
  Juddii 
  ; 
  he 
  gives 
  no 
  description, 
  but 
  in 
  a 
  

   short 
  note 
  refers 
  to 
  it 
  as 
  " 
  a 
  long 
  Belemnite 
  from 
  Speeton 
  in 
  the 
  pos- 
  

   session 
  of 
  Mr. 
  Lee. 
  ... 
  It 
  agrees 
  nearly 
  with 
  a 
  species 
  found 
  in 
  the 
  

   Kimmeridge 
  Clay 
  near 
  Oxford." 
  If, 
  therefore, 
  it 
  should 
  hereafter 
  be 
  

   thought 
  necessary 
  to 
  grant 
  this 
  form 
  specific 
  recognition, 
  Phillips's 
  

   name 
  should 
  have 
  preference. 
  Professor 
  A. 
  Pavlow, 
  who 
  has 
  exa- 
  

   mined 
  my 
  collection, 
  seems 
  to 
  recognize 
  among 
  these 
  forms 
  the 
  Bel. 
  

   magnificus, 
  D'Orb., 
  a 
  near 
  ally 
  of 
  Bel. 
  ahsolutus. 
  Fisch.* 
  

  

  Belemnites 
  lateralis, 
  Phil. 
  

  

  This 
  abundant 
  species 
  shows 
  a 
  considerable 
  range 
  of 
  variability. 
  

   The 
  commonest 
  form 
  is 
  short 
  and 
  verjr 
  stout, 
  but 
  another 
  variety 
  

   attains 
  a 
  greater 
  length 
  in 
  proportion 
  to 
  its 
  breadth. 
  The 
  shortness 
  

   of 
  the 
  former 
  variety 
  is 
  often 
  accentuated 
  by 
  the 
  decayed 
  and 
  deeply 
  

   eroded 
  condition 
  of 
  many 
  of 
  the 
  guards, 
  which 
  tends 
  to 
  reduce 
  the 
  

   length 
  considerably 
  f. 
  I 
  have 
  not 
  noticed 
  any 
  difference 
  in 
  the 
  dis- 
  

   tribution 
  of 
  these 
  varieties. 
  

  

  Reference 
  has 
  already 
  been 
  made 
  to 
  the 
  doubtful 
  form 
  in 
  the 
  

   Coprolite- 
  bed, 
  which 
  may 
  possibly 
  be 
  only 
  a 
  variety 
  of 
  this 
  species 
  ; 
  

   and 
  also 
  to 
  the 
  species 
  resembling 
  Bel. 
  lateralis 
  which 
  occurs 
  in 
  the 
  

   zone 
  of 
  Bel. 
  semicanaliadatus 
  ?. 
  

  

  This 
  latter 
  form 
  Phillips 
  seems 
  to 
  have 
  included 
  with 
  B. 
  lateralis, 
  

   and 
  may, 
  I 
  think, 
  have 
  figured 
  it 
  in 
  the 
  inner 
  outline 
  of 
  that 
  species 
  

   (in 
  * 
  Geol. 
  of 
  Yorks.' 
  3rd 
  ed. 
  pi. 
  xxv. 
  f. 
  8). 
  Respecting 
  it 
  he 
  notes 
  

   (p. 
  334) 
  that 
  it 
  "corresponds 
  to 
  what 
  has 
  been 
  called 
  B. 
  semisul- 
  

   catus 
  etc. 
  of 
  Brongniart." 
  But 
  the 
  difference 
  between 
  the 
  adults 
  of 
  

   the 
  species 
  in 
  the 
  upper 
  zone, 
  which 
  are 
  never 
  large, 
  and 
  the 
  massive 
  

   guards 
  of 
  Bel. 
  lateralis 
  is 
  very 
  striking 
  in 
  every 
  way 
  ; 
  and 
  even 
  

   when 
  specimens 
  of 
  the 
  same 
  size 
  are 
  compared, 
  it 
  is 
  easy 
  to 
  see 
  

   the 
  distinction 
  at 
  once, 
  for 
  while 
  Bel. 
  lateralis 
  shows 
  a 
  gradual 
  

   thickening 
  from 
  apex 
  to 
  base, 
  the 
  former 
  species 
  attains 
  its 
  greatest 
  

   thickness 
  about 
  halfway 
  down 
  the 
  guard 
  and 
  shows 
  a 
  well-marked 
  

   constriction 
  towards 
  the 
  phragmocone. 
  I 
  think 
  these 
  two 
  forms, 
  

  

  * 
  A. 
  Pavlow, 
  ' 
  Etudes,' 
  &c. 
  (sup. 
  cit.) 
  p. 
  42. 
  

  

  t 
  M. 
  N 
  ikitin 
  recognizes 
  in 
  these 
  varieties 
  (1) 
  Belemnites 
  corpidevtus, 
  Nik., 
  and 
  

   (2) 
  Bel. 
  ritssie?i$is, 
  d'Orb., 
  which 
  occur 
  in 
  the 
  " 
  Upper 
  Yolga 
  beds 
  " 
  of 
  Russia. 
  

   (Quelques 
  Excursions, 
  &c. 
  p. 
  40.) 
  

  

  